The McGonagalls were feared in the Hindu Kush. They were also feared in camp, whenever there was a round to be bought.

Falling, I fell forever into fathomless blackness. Tumbling, I was helpless. Into what, I could not know, only that plunge I must, and for eternity. Was this Hell itself, was it Pandaemonium through which I plummetted?

And yet, there were glimpses, terrible, desperate fleeting visions, of a world so dear. Of a world forever closed to me. Our bedroom, at home, the smell of lavender. The lovely face of my wife. My bull-pup, Wellington. Or was it the maid? I never could tell them apart by gas-light. Then I was falling, away from them, my screams silent as nightmare's cries.

I was asleep in my favourite chair, before a roaring fire. Tenderly, Polly, my second wife, lifted the book from my lap. I could see the cover: The Art of The Pygmy Statuette-Maker. Somewhere, a band was playing the Gay Gordons. The arms. The terrible, flapping, flailing arms. I was falling, backwards, into vastness.

A shingle beach, the sound of the Gay Gordons again. It was cold. I was trapped inside a letter-box. Through the slit I saw Humes, running for his life. There was a terrible cracking and a crashing. Broken spears filled the air. Humes was flapping, failing to fly, falling. Then came the walruses, to feast upon his shattered body. Atop the beetling cliff stood Professor Morris Varty, playing a vainglorious trombone. I roared in grief, my cries echoing inside the letterbox. I was falling.

Until, one morning of pale yellow daylight, I awoke to find Polly by my bedside, reading Morte D'Arthur by Tennyson. I hardly dared to believe the evidence of my senses, afraid that I must be flung off into the void of nightmare again at any second. But it did not happen. I was filled with an unbearable sense of pity for my poor wife.

"James!" she sighed. "You have returned to us."

I managed to mutter: "My poor dear Polly, how long have you been keeping vigil at my bedside?"

She smiled, as she adjusted the counterpane. "These three days you have been unconscious. It has been simply awful."

Tears started in my eyes. "Oh Polly", I moaned. "Don't tell me you have been forced to read Tennyson for three whole days!" And I sobbed, in sheer abandon of grief.

"I am afraid so", she replied. "It was that or something by Thomas Hardy, and you know how that always makes me laugh. I judged raucous laughter particularly inappropriate at this time."

Thus, I re-entered my life. It was as if I had been born a second time, introduced gently to the world by my wife's infallible sense of propriety.

Of course, I had not forgotten what had occurred. The dreadful memories had haunted my sleeping mind. That I had been knocked unconscious in the villa of Colonel Clavicord, that our investigation had proved an utter failure, this was hard to bear.

That Shylock Humes was dead, this was impossible to accept.

But we are resilient creatures, and life goes on. Within two days I was back on my feet. Then I sat down again, for I had breakfast to eat and a telegram from Scotland Yard to read.

"Inspector Livingstone Stanley asks if I am fit enough to meet him at 221b Candlestick Maker Street at 10:00 this morning", I said to Polly. "They have a lead they want to explore."

"Then you must go. It will do you good. I think it will help you enormously, to do something, to act, in the pursuit of justice and an explanation of what happened to Mr Humes."

I looked at my wife over the teapot. The elephant tea-cosy had been a present from her former employer, Mrs Pinkerton-Singh, who had married an Indian exporter of circus animals. "My dear, you are precisely right. As ever, your thoughtfulness strikes home exactly."

She smiled. "Besides, you are dreadfully in the way, here. I have not been able to have the Aspidistra Club round while you have been convalescing. It's my turn to host, you know."

It was with a heavy heart that I rang the bell at Candlestick Maker Street that morning. The familiar weathered, soot-blackened facade ought to have cheered me, but it brought back waves of barely-suppressed grief. It was Mrs Dudson, back from her sister Effie at Ecclefechan.

We looked at each other. There were tears. A strong, manly shoulder was required, to comfort the weaker sex. When I had stopped weeping, Mrs Dudson patted me on the head and said:

"Best thing you can do, Doctor Flotsam, is help the Inspector to catch whoever it is what done this thing. Do it for him" she whispered, before disappearing into her rooms.

Inspector Stanley Livingstone Stanley was standing before the fire, in the sitting-room. I was glad. If he had stood after the fire, we would never have got started. As it was, the situation promised to be a fruitful one. There were fresh apples in the bowl.

"Well, well, Doctor Flotsam", he said, extending his hand. His double-jointed hand always made me shudder. "How are you doing, doctor? You have been in the wars, indeed."

"I have, Inspector", I agreed. "But I would go through it all again, if only we could bring him back."

We both looked at the empty chair by the fireplace, standing there like a derelict house. Humes' taste in chairs always did repulse me.

"It's strange", said Livingstone Stanley, "but it's almost as if he was still with us. As if his spirit was in this room."

"That will be the tobacco and brandy fumes", I explained. "Nobody will ever get the odour of Nelson's Navy Cut Extra Rough Shag and Vintage Albanian Brandy out of the wallpaper after all these years."

"But take a seat, Inspector", I invited, sitting down myself. Then I had to shout "No, Inspector, don't take the chair downstairs. Bring it back in here and sit on it. I made that mistake in Part I of this rubbish."

Once we were ensconsed in front of the fire (I felt quite the naughty boy; I had never been ensconsed in front of a fire before; I usually did my ensconsing alone, in my parlour at home, after Polly had gone up); once we were seated comfortably, I spoke again.

"So, Inspector, what has occurred in the way of a lead in the case?"

The policeman shifted in his seat. Why was he wearing a shift in this weather? He began to recount what had happened:

"I don't know how much you remember or have been told, doctor, but this is what happened the other night. We waited outside the house for Mr Humes to signal on the police whistle as instructed. But nothing was heard. It was only when we heard a commotion from the building, and people started running out, that we knew something had gone wrong, and it was time to go in."

He shook his head, staring into the glowing coals. I offered him a cigar. "Thank you, doctor. I'll never forget the sight of Queen Victoria running across that lawn alongside a Mock Turtle and Robin Hood's Merry Men, to the day I die."

It was a sombre moment. We sat in silence, contemplating the horrible image. Outside, a street seller yelled "Mutton Pies, Mutton Pies, Fresh Last Week!" Then Livingstone Stanley continued.

"Of course, we arrested as many as we could of those who were trying to run for it. The cells are still full of all these characters in fancy dress, though I don't mind telling you, we've got nothing on any of them. They're all pleading ignorance, and we've no evidence.

"Arbuthnot Williams and me went in, and we collared as many as we could from that ballroom, but there were only a dozen or so left. All small fry, various tradespeople, one or two from Europe, a couple from America. Again, we can't charge them with anything."

I sat up. "But Inspector, I saw Humes fall. Those two walruses, the pantomime duck, the Afghan sailor, they must have seen something? And the band, the bassoon, bugle and jew's harp? Surely...?"

Livingstone Stanley looked at me indulgently, compassionately, as one listening to a child's account of a nightmare. "Yes, doctor, I know that is what you think you saw. Your wife told us all that. Apparently you kept mumbling about all that while you were ill.

"The thing is, we didn't find anyone in any costume answering to those descriptions."

"But I saw them. I would swear to it."

"Yes, I know, but..."

"And what about, what have you done with, you know...?"

He looked into the fire again, avoiding my gaze. "Well, we removed the body to the morgue. I have to tell you, doctor, it wasn't pretty. If it wasn't for his clothes, we would have been hard put to it to identify him."

"I know that. I saw him fall. I saw them trample him afterwards. The devils, there must be something we can do!"

The Inspector blew out a cloud of smoke. "Oh, we'll find the other minions, don't you worry. I've got men scouring the streets." He shook his head. "The trouble is, we haven't managed to recover the Red Emerald, and, after what Mr Humes told us about the villains in charge of the whole caper, we don't expect to lay our hands on those gentlemen any time soon, if at all."

The hideous sound of Professor Morris Varty playing a vainglorious trombone played through my mind. It was unthinkable to let that continue. "But that is a counsel of despair, Inspector. There simply has to be a way out of this mess. What would Humes have done? That must be our approach."

"Well, doctor", replied Livingstone Stanley. "We aren't quite at the despair stage just yet. We do have this lead. You never know where that might take us."

I sighed. "Well, what is this lead of which you speak?"

He handed me a letter, scribbled on cheap paper. I read it aloud. It had always been my role to read letters and telegrams out loud. Humes had always been too idle to read them himself. Of course, if he had simply read them himself, there would have been no way to apprise the reader of their contents. Not that anybody reads this rubbish anyway, but that is beside the point, as the man said, indicating the trainspotter. This is what I read:

I handed the missive back to Livingstone Stanley, shrugging my shoulders. "This may be a mere whim, Inspector. Perhaps it is the work of a crank."

"We thought of that, doctor", said the Inspector. "But we had our experts go through it with a fine-toothed comb."

"And what did they conclude?" I enquired.

"They said it was a mere whim, the work of a crank. And yet, I am not so sure."

"Go on", I urged.

"Well, only a Scotsman would talk like that, doctor. And, if we once accept that, then we can only conclude that he is very likely to write like it too. And when we add the name of our correspondent to this litany, then the accumulated evidence begins to stack up like the tea-crates at Rotherhithe Docks."

I was not convinced. "Your logic is watertight, Inspector", I conceded, but surely..."

I was interrupted by a noise like the bourdon bell, named Emmanuel of Notre Dame cathedral. It was the doorbell, making the very walls tremble. Humes had brought the bell back as a souvenir of The Adventure Of The One-Legged Can Can Dancer. It was yet another reminder of my late friend that sent a dagger to my heart.

Inspector Stanley Livingstone Stanley stood up. I was grateful. If he had stood down, I should have been bereft of the aid of Scotland Yard. "Well, doctor", he said. "Whoever he is, our visitor is punctual, if nothing else."

I glanced at the clock. It said a quarter to three. I would get no help there. I was forced to accept the Inspector's estimate of the time, and as for our visitor's punctuality, that too I would have to take on trust, loth though I usually was to rely on trust since that previous Christmas when Mrs Dudson had been ill and Humes and I had trussed the goose and ended up almost choking on the string.

And then there was Mrs Dudson, in the time-honoured way that sent fresh waves of grief coursing through me, introducing our latest visitor.

"Mr Jock 'The Kilt' McStoater, gentlemen", she said, and disappeared. I had never worked out how she did that. It must have been something to do with mirrors and false partitions, but it was all too quick for me.

Our visitor entered the room. His appearance was most extraordinary. He must have been tall, once, but now he stooped with age. He was thin, and had a crooked gait. Why he carried a gait was a mystery to me. Perhaps he had bought it for the end of his garden path. He walked with the aid of a gnarled and twisted stick. Either that, or the stick relied upon the aid of a gnarled and twisted walker.

He was dressed like a Highlander of the North Country, with kilt, sporran, sgian dubh dagger, ghillie brogues and on his head was a tam o shanter.

I looked at Inspector Livingstone Stanley. He shrugged his shoulders. "It's all right, Inspector", I reassured him. "I was with the McGonagalls in the Hindu Kush in '73. I learned a smattering of their tongue. I will try to speak to him using that."

The McGonagalls were universally feared in the Hindu Kush. They used to recite enormously long doggerel poems to the local tribesmen and beat them into submission using blank verse alone. They were also feared in camp, whenever there was a round to be bought. I thought hard, recalling the smattering I had picked up (and the ointment I had needed to get rid of it).

I looked McStoater in the eye. They respected that, I remembered. Besides, he only had the one eye. "Whisky?" I proffered.

He sipped his whisky. Livingstone Stanley was impatient to get on. "Look, Mr McStoater, we appreciate you've had a long journey, but these are serious matters in which we are embroiled. What is this lead of which you speak in your letter? Time is of the essence."

Our extraordinary visitor looked at each of us in turn. He grinned like a goblin. It was as if he were toying with us. "Ochaye the noo, hen, an' ye're the skintlin' yin an nae mistake! Och, 'tis nothin, nothin' at a', an a' an a', the noo the naw the noo."

"Look here, Jocko", said Livingstone Stanley, "spit it out, chummy, and be quick about it. If you don't sing like the canary, I'll have you on a charge of wasting police time faster than you can say 'Bonnie Prince Charlie was a useless poofter'. You'll be getting plenty of porridge where you're going if you catch my drift. Scrotes like you make me..."

I sighed, but McStoater merely smiled a smile as crooked as his stick. "Och, 'tis noathin'. I jest knaw where the jewel ye seek is, thet's aw, the noo the naw."

"What?" we both gasped. "If you are having us on", said the Inspector, "I'll have you..."

"'Tis in theer", said the Scot. "Aye, 'tis in th' bogpipes yonder, d'ye ken, the noo?"

We followed where his crooked stick pointed, though, Goodness knows, it was a tortuous journey following a stick such as that. But eventually we arrived at our destination. There, in the corner, above the table on which my friend Shylock Humes had kept his violin, hung the bagpipes that Humes had been presented with by the McBagpipe of McBagpipe, after The Adventure Of The Untossed Caber.

"What have we got to lose?" I said to Livingstone Stanley. "We may as well pursue this, now we have started."

I took down the bagpipes with the embroidered message of "A Present From The McBagpipe of McBagpipe" on their belly, and brought it to our visitor.

"Mr McStoater, this is becoming ridiculous", I pleaded. "Please explain your meaning. My friend is a fully-trained police inspector. I cannot restrain him much longer. I beg you to tell us what is going on."

"That's right, Sonny Jim", said Livingstone Stanley, "if you don't come clean and tell us what's in those bagpipes, then you'll find that those bagpipes might end up in you, if you get my drift."

Shaking our heads, we turned to face the fireplace. "We've been in some rum situations together, doctor", said Livingstone Stanley, "but this beats the lot."

"We'll give him a chance", I said. "Then you can nick him. If he doesn't come up trumps you can put the derbies on him." Good grief, I was beginning to sound like a policeman.

But further thought was banished from my mind, to be replaced by such a caterwauling as I had never heard since Humes and I saw Linguini in Madame Butterfly at Covent Garden. McStoater was playing the bagpipes!

I spun around. Livingstone Stanley spun around. There, in front of us, in the very sitting room at Candlestick Maker Street, right there, right then, we saw a sight that confounded and bewildered us into a bewildered and confounded silence.

We stood, amid the bizarre din of bagpipe music, our mouths agape, looking at the very last thing we had expected to be looking at, at that, or indeed any moment whatsoever.

Mr Jock 'The Kilt' McStoater had vanished, to be replaced by Shylock Humes, who was playing the bagpipes he had once been given by The McBagpipe Of McBagpipe. Not only that, he was also holding up to us the Red Emerald itself.